Robert : Earl of Grantham - Hugh Bonneville

Robert, Earl of Grantham. (Hugh Bonneville) Robert Grantham has lived an uncomplicated life until now. He married his wife, Cora, an American heiress, in 1889, largely for her money and although there is no denying her cash put the estate back on its feet, over time they have grown to love one another deeply. The marriage contract, as we know, stipulated that her fortune, once invested in the estate, was inseparable from it. Neither Robert nor his wife anticipated that this clause (demanded by his late father) would cause problems, since they both confidently expected to have a son and heir. The trouble is they didn’t. They had three daughters, Mary, Edith and Sybil.

Cora : Countess of Gratham - Elizabeth McGovern

Cora, Countess of Grantham. (Elizabeth McGovern) Cora is the beautiful daughter of Isidore Levinson, a dry goods multi millionaire from Cincinnati. She arrived in England, with her mother, in 1888, at the age of 20, and was engaged to Robert, Viscount Downton, as he then was, by the end of her first season. She accepted the clause, at the insistence of her father-in-law, assuming she would have a boy. Now that the cousin she did at least know is dead, the new heir is a distant cousin.

Violet Dowager Countess of Grantham - Maggie Smith

Violet, Dowager Countess of Grantham. (Dame Maggie Smith) is Robert’s mother. She is immensely proud, immensely loyal to her son. She was born the daughter of a baronet. Publicly, Violet supports the arrangements made by her late husband but in reality, once Patrick is dead, she favours her granddaughter, Mary, over some distant stranger. This paves the way for an unholy alliance between the two Countesses, as they plot against Robert to overturn the arrangements. When the cross-breed heir arrives, with his middle class mama, she finds the situation intolerable, even if she, like Cora, sees one solution in Matthew’s marrying Mary.

The Sisters - Lady Mary : Lady Edith : Lady Sybil Crawley

The Earl and Countess of Grantham's Three Daughters, The Eldest Lady Mary is played by Michelle Dockery, Lady Edith is played by Laura Carmichael and Jessica Brown-Findlay stars as The youngest daughter Lady Sybil.

Lady Rosamund Painswick - Samantha Bond

Lady Rosamund Painswick. (Samantha Bond) Lady Rosamund is Robert’s only sister. She did not marry a great aristocrat and has no country seat, but the late Marmaduke Painswick, a banker, was immensely rich, so she has a good deal of freedom of movement. She is devoted to Robert, but she feels it her duty to speak her mind on every possible occasion. Her interference in her niece’s (Mary) decisions has a potentially disastrous result

Isobel Crawley - Penelope Wilton

Isobel Crawley. (Penelope Wilton) Isobel is Matthew’s widowed mother. She is the daughter of a doctor (her husband studied under her father) and she comes from the professional middle class. She embodies an entirely different set of values to those of the main family, being far better educated than either Violet or Cora, and before long she is at loggerheads with Violet. She is intensely proud of her son and not because he has turned out to be the heir to a great name. If anything, she thinks he is throwing away a brilliant career

Matthew Crawley - Dan Stevens

Matthew Crawley is a third cousin, once removed, of Lord Grantham. A practicing attorney, Matthew now finds himself heir to a large estate and is invited to move there. He eventually agrees, but only if he can continue to work. Cora is partly infuriated by this interloper and partly determined that he will marry one of her daughters.

Lavinia Swire - Zoe Boyle

Lavinia Catherine Swire (played by Zoe Boyle) was the fiancée of Matthew Crawley. She is the daughter of London solicitor Reggie Swire whom she has been very close to ever since her mother's death during her early childhood. In 1912, she brings private papers of her uncle Jonathan Swire, a Liberal minister, to Sir Richard Carlisle since Sir Richard was about to financially ruin her father. The papers Lavinia stole inadvertently helped create the Marconi scandal. She first met Matthew when he was back in England on leave and they later become engaged. When Matthew returns from the First World War injured she refuses to leave him despite being told that he will never walk again or father children. Lavinia dies at Downton of Spanish influenza after Matthew regains use of his legs and shortly before their wedding.

Sir Richard Carlisle - Iain Glen

Lord Hepworth - Nigel Havers

Nigel Havers plays suave Lord Hepworth, an old family friend who joins the cast of the festive special. He attends a Christmas shooting party and charms Lady Rosamund (Samantha Bond), wealthy widow and sister to Earl Granthem.

Martha Levinson - Shirley Maclaine

Lady Rose Aldridge - Lily James

Lady Rose Aldridge (née MacClare) (b. 1902) is the youngest child of Hugh and Susan MacClare, the niece of Agatha and Louisa, the younger sister of James and Annabelle, the sister-in-law of Annabelle's husband, the great-niece of Violet Crawley, the Dowager Countess of Grantham, the wife of Atticus Aldridge, the daughter-in-law of Daniel and Rachel Aldridge and the mother of Victoria Rachel Cora Aldridge.In Autumn 1920, she visits Downton Abbey and stays with Violet in the Dower House. She returns a year later, in September 1921, when the Crawley family visits her home at Duneagle Castle, where it is agreed that Rose will go to stay with them when her parents go to India. She moves there sometime between September 1921 and February 1922. During her longer stay, she has relationships between Easingwold under-gardener Samuel Thawley, Sir John Bullock, and singer Jack Ross. In 1923, she is presented in London and at her debutante ball she dances with the Prince of Wales. In Summer 1924, she meets Atticus Aldridgeand shortly after they marry and go on a honeymoon to Venice. At Downton, she and Atticus celebrate the latter's first Christmas. Shortly after, she moves to New York with Atticus. In September 1925, she gives birth to the couple's daughter, whom they name Victoria Rachel Cora Aldridge after Atticus's mother and Cora respectively, and the couple, sans Child, return to Downton for the 1925-1926 new years celebrations.​